Significant Accounting Policies - Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Total cost	$ 14,292	$ 12,833
Total property, plant and equipment, net	11,644	10,602
Tampa Electric [Member]
Property Plant And Equipment [Line Items]
Less accumulated depreciation	(3,158)	(2,937)
Construction work in progress	949	1,219
PGS [Member]
Property Plant And Equipment [Line Items]
Less accumulated depreciation	(687)	(664)
Construction work in progress	248	151
Total property, plant and equipment, net	2,251
Electric Generation [Member]
Property Plant And Equipment [Line Items]
Total cost	6,300	5,395
Gas Transmission and Distribution [Member]
Property Plant And Equipment [Line Items]
Total cost	2,567	2,360
General Plant and Other [Member]
Property Plant And Equipment [Line Items]
Total cost	$ 1,020	946
Minimum [Member] | Electric Generation [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	21 years
Minimum [Member] | Gas Transmission and Distribution [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	15 years
Minimum [Member] | General Plant and Other [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	3 years
Maximum [Member] | Electric Generation [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	60 years
Maximum [Member] | Gas Transmission and Distribution [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	75 years
Maximum [Member] | General Plant and Other [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	71 years
Electric Transmission [Member]
Property Plant And Equipment [Line Items]
Total cost	$ 1,109	1,068
Electric Transmission [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	10 years
Electric Transmission [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	77 years
Electric Distribution [Member]
Property Plant And Equipment [Line Items]
Total cost	$ 3,296	$ 3,064
Electric Distribution [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	10 years
Electric Distribution [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated useful lives	59 years